Cant get my injector pulsewidth below 3.0 ms

[Dirk Diggler]

at idle. I think this may be causing a lot of my issues with my idle misture being really rich. The ve table no matter how much i fool with it doesnt seem to drop the PW

[dfe1]

Don't mean to state the obvious, but sometimes the obvious isn't. The minimum pulse width you're going to see is a function of injector size. I don't know your specific combination, but with stock injectors, you're going to see 3.5 to 4.5 ms at idle depending on engine size, mods etc. Unless you have REALLY large injectors, 3 ms should be in the ballpark. Try changing the IFR-- it has a much more dramatic impact on pulse width. Keep in mind that if you're in closed loop, fuel trim will have an impact on pulse width.

[Dirk Diggler]

The injectors are Racetronix 32 lbs/hr injectors

Mods are

230/232 595/ 585 110 +0
LSX 90/90
Open loop SD tune

Because i cant lean out the mixture at idle this is the major reason I feel i am getting surging and hanging idle while sitting still. I continue lowering the ve table and I cant seem to get teh commanded to match the actual 13.0 commanded and high 11's low 12's actual. If the dam thing idles for to long it starts fouling out my plugs. Eg was waiting in the Mcd's drive thru for some food by the time i left the car was mising like crazy and loading up. After two miles of driving it cleared right back up and ran like a champ except for at idle...

I am going to go back and check my IFR values and see what happens

[bink]

HumpinSS - did you try the "effective area" translocation - I thought you said you were going to try that ??

What does your Timing do as it surges??

Cheers,
joel

[Dirk Diggler]

I tried the effective area and got all th way to 36 with no changes. Timing while surging goes from 24-34 but when it isnt surging its at a steady 24*

[bink]

I tried the effective area and got all th way to 36 with no changes. Timing while surging goes from 24-34 but when it isnt surging its at a steady 24*


Does it surge (at idle) as the IAT changes??
I mean as you are sitting still with a nice even idle ....does it randomly surge?...and have you checked the IAT and/or ECT at initiation of surging??

[Dirk Diggler]

It seems to do it a full ooperating temps usually after cooming to a stop at a light or so. It doesnt recover very well

[GMPX]

Dirk,

We hope to get some new Injector tables in for V7.2 release that 'might' help.
One of our Beta testers has had similar issues with big injectors.

Cheers,
Ross

[bink]

Dirk,

We hope to get some new Injector tables in for V7.2 release that 'might' help.
One of our Beta testers has had similar issues with big injectors.

Cheers,
Ross

This sounds nice :D .

Have you tried bumping RAF by 0.10 g/sec at a time?

Remember the only way to reset LTITs is too disconnect (pull fuses) the pcm (key ON) and wait a minute or two.

Did you reset the LTITs or wait for "learning" with the "Eff. Area" change?

jfpilla and Nick have shown that there is a "sweet spot" relationship between "IAC Park" values and "Base Running Airflow" values . FWIW.
Are your IAC Park values stock??

Sorry if this rambles...I'm just thinking and typing...out loud???

[Dirk Diggler]

IAC park is stock now. I kinda got frustrated and set all my idle tables back to stock since none of the changes seemed to affect my idle quality. I keep forgetting to pull the fuses after a flash

[Dirk Diggler]

Dirk,

We hope to get some new Injector tables in for V7.2 release that 'might' help.
One of our Beta testers has had similar issues with big injectors.

Cheers,
Ross

Great hopefully this will help. Its starting to drive me nuts and its burning copious amounts of gas

[Black02SS]

I am having the same problem, but I am using the stock 28lb'ers. Any ideas?

[bink]

I am having the same problem, but I am using the stock 28lb'ers. Any ideas?

What are your mods and what tables have you changed (settings)??

[Black02SS]

I am having the same problem, but I am using the stock 28lb'ers. Any ideas?

What are your mods and what tables have you changed (settings)??

LS6 Heads
F13 Cam
LS6 intake
225lph Inline
225lph Intank
Stock Inj.
ASP Pulley
S2 Throttle Body
Pasecetter Longtubes
3" True Duals

I am in SD open loop as well. I have managed to get my idle AFR to 14.3, but my injectors are still in the 3.2ms range. Only major changes are to timing tables and ve tables. IFR table is multiplied by 3% to compensate for the added fuel pressure (about 62psi).